Radisson Reports Highest Grade Drill Intercepts Achieved to Date Beneath the Historic O'Brien Gold Mine Including 89.36 g/t Gold over 3.7 Metres and 60.75 g/t Gold over 2.1 Metres

Radisson Mining Resources Inc. (TSXV: RDS,OTC:RMRDF) (OTCQB: RMRDF) ("Radisson" or the "Company") is pleased to announce assay results from new drill holes completed at its 100%-owned O'Brien Gold Project ("O'Brien" or the "Project") located in the Abitibi region of Québec.

Four of the drill holes reported today are wedges completed from the previously reported pilot hole OB-24-337, the deepest hole ever drilled at the Project and the first drilled directly below the historic O'Brien Mine workings. This pilot hole, and the first three wedge-extensions drilled from it (OB-24-337W1 to W3) all returned multiple, high-grade gold intercepts, delineating a large zone of gold-bearing veins with good continuity (see Radisson News Release dated April 2, 2025). Now, an additional four wedges (OB-25-337W4 to W7) demonstrate the scale of this zone with the highest-grade intercepts yet achieved. Highlights include:

• OB-25-337W7 intersected 89.36 grams per tonne ("g/t") gold ("Au") over 3.7 metres, including 293.0 g/t Au over 1.1 metres and 16.43 g/t Au over 8.1 metres, including 60.75 g/t Au over 2.1 metres and 9.69 g/t Au over 1.3 metres;

• OB-25-337W5 intersected 47.70 g/t Au over 1.0 metres and 5.25 g/t Au over 4.0 metres, including 17.90 over 1.0 metres;

• OB-25-337W6 intersected 6.45 g/t Au over 3.5 metres, including 18.80 g/t Au over 1.0 metres and 3.57 g/t Au over 12.0 metres, including 6.51 g/t Au over 1.0 metre and 3.70 g/t Au over 4.4 metres, including 7.11 g/t Au over 1.5 metres.

Radisson is also reporting, today, results from ten shallower holes drilled adjacent to the historic mine workings on "Trend #0", including drill holes in and around the former "Jewellery Box" zone (see Radisson News Release dated December 9, 2024). Recall that drill hole OB-24-347 returned 643.1 g/t Au over 2.1 metres, including 1,345.0 g/t Au over 1.0 metres on what is interpreted to be the near surface upwards extension of the famous high-grade and narrow mining stope. Highlights include:

• OB-25-370 intersected 4.32 g/t Au over 6.5 metres, including 10.49 g/t Au over 2.1 metres;

• OB-25-372 intersected 7.05 g/t Au over 2.5 metres, including 15.95 over 1.0 metre.

Figure 1: Long Section and Plan View of Gold Vein Mineralization and Mineral Resources at the O'Brien Gold Project, with Today's Drill Holes Illustrated

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Matt Manson, President & CEO, commented: "Since last December, we have been reporting the delineation of a series of high-grade gold-bearing veins developed over a large area up to 500 metres below the base of the historic O'Brien Gold Mine. In today's news release we are reporting the highest-grade intercepts returned to date from this area, with the results of four new wedges drilled from our initial pilot hole. We are now delineating up to six mineralized zones over hundreds of metres, which appear related to mapped veins at the base of the former mine and which are outside the scope of conceptual mine plan contained in our recently reported Preliminary Economic Assessment (see Radisson News Release dated July 9, 2025). A priority of our ongoing 50-60,000 metre drill program at O'Brien is large step outs below the current mineral resources and the historic mine in a 'proof-of-concept' approach to test the potential extension of the O'Brien mineralizing system to 2 kilometres depth. To date, this strategy has been remarkably successful, with important implications for the future scale of the Project."

Matt Manson continued: "We are also reporting today several shallower drill holes targeting the surface projection of the famous "Jewellery Box Zone", rediscovered by Radisson with bonanza grades late last year, as well as the downward extension of our mineral resource block model on "Trend #0" adjacent to the Jewellery Box stope. Both target areas have returned high-grade intercepts, demonstrating extensive gold mineralization in and around this target area."

Table 1: Assay Results from Drill Holes OB-24-356 to OB-25-374 and OB-25-337W4 to W7

Notes on Calculation of Drill Intercepts:
The O'Brien Gold Project Mineral Resource Estimate Published on July 9, 2025 ("MRE") utilizes a 2.20 g/t Au bottom cut-off, a US$2,000 gold price, a minimum mining width of 1.2 metres, and a 40 g/t Au upper cap on composites. Intercepts presented in Table 1 are calculated with a 3.00 g/t Au bottom cut-off. Sample grades are uncapped. True widths, based on depth of intercept and drill hole inclination, are estimated to be 30-80% of core length. Table 2 presents additional drill intercepts calculated with a 1.00 g/t bottom cut-off over a minimum 1.0 metre core length so as to illustrate the frequency and continuity of mineralized intervals within which high-grade gold veins at O'Brien are developed. Lithology Codes: PON-S3: Pontiac Sediments; V3-S, V3-N, V3-CEN: Basalt-South, North, Central; S1P, S3P: Conglomerate; POR-S, POR-N: Porphyry South, North; TX: Crystal Tuff; ZFLLC: Larder-Lake-Cadillac Fault Zone.

Gold Mineralization at O'Brien

Gold mineralizing quartz-sulphide veins at O'Brien occur within a thin band of interlayered mafic volcanic rocks, conglomerates, and porphyritic andesitic sills of the Piché Group occurring in contact with the east-west oriented Larder Lake-Cadillac Break ("LLCB"). Gold, along with pyrite and arsenopyrite, is typically associated with shearing and a pervasive biotite alteration, and developed within multiple Piché Group lithologies and, occasionally, the hanging-wall Pontiac and footwall Cadillac meta-sedimentary rocks.

As mapped at the historic O'Brien mine, and now replicated in the modern drilling, individual veins are generally narrow, ranging from several centimetres up to several metres in thickness. Multiple veins occur sub-parallel to each other, as well as sub-parallel to the Piché lithologies and the LLCB. Individual veins have well-established lateral continuity, with near-vertical, high-grade shoots developed over significant lengths. Based on the historic data available, it is clear that the former mine was "high-graded", with mining focussed on a main central stope and parallel veins identified but left undeveloped.

The historic O'Brien mine produced over half a million ounces of gold from such veins and shoots at an average grade exceeding 15 g/t Au and over a vertical extent of at least 1,000 metres. Modern exploration has focussed on delineating well developed vein mineralization to the east of the historic mine, with additional high-grade shoots becoming evident in the exploration data over what has been described as a series of repeating trends ("Trend #s 0 to 5").

Since the end of 2024, Radisson has been delineating a series of high-grade veins beneath the historic workings of the O'Brien mine with a series of wedge-extensions drilled from the pilot hole OB-24-337, which intersected 242.0 g/t Au over 1.0 metre within a mineralized interval that averaged 31.24 g/t Au over 8.0 metres at approximately 1,500 metres vertical depth. With today's news release, assay results from a total of 7 wedges have now been reported and up to six gold-bearing veins have been delineated over an area of approximately 250 metres (east-west) by 250 metres (vertical). These veins appear to correspond to veins mapped at the base of the historic mine at 1,000 metres deep, approximately 300 to 500 metres above the new intercepts.

Radisson's vein modelling is undertaken dynamically as drilling proceeds and is used to guide future exploration and, ultimately, domaining for future resource estimation. Beneath the historic mine, vein V3-S_20 intersects OB-24-337W2, W3 and W7 and is further supported by underground mapping in an exploration drift located to the south of the main mined out vein at level 3450 (feet). Vein V3-C_03 is intersected by the pilot hole and all seven wedges and is further supported by underground mapping and the historic stope locations. Vein V3-N_02 is intersected by the pilot hole and all seven wedges and is further supported by historic underground drilling from the 3450 level. V3-N_03 is intersected by all seven wedges. With the new drill holes published today, two new veins have been added to this developing model: POR_S-14 intersected by the pilot hole plus three wedges, and CONG_15 which is intersected by wedges W2, W4, W6 and W7.

Based on drilling complete to the end of 2022, and a recently published Preliminary Economic Assessment for the Project (see Radisson news Release dated July 9, 2025) the Project has estimated Indicated Mineral Resources of 0.58 million ounces (2.20 million tonnes at 8.2 g/t Au), with additional Inferred Mineral Resources of 0.93 million ounces (6.67 million tonnes at 4.4 g/t Au). Mineral Resources that are not Mineral Reserves do not have demonstrated economic viability.

QA/QC

All drill cores in this campaign are NQ in size. Assays were completed on sawn half-cores, with the second half kept for future reference. The samples were analyzed using standard fire assay procedures with Atomic Absorption (AA) finish at ALS Laboratory Ltd, in Val-d'Or, Quebec. Samples yielding a grade higher than 10 g/t Au were analyzed a second time by fire assay with gravimetric finish at the same laboratory. Mineralized zones containing visible gold were analyzed with metallic sieve procedure. Standard reference materials, blank samples and duplicates were inserted prior to shipment for quality assurance and quality control (QA/QC) program.

Qualified Persons 

Disclosure of a scientific or technical nature in this news release was prepared under the supervision of Mr. Richard Nieminen, P.Geo, (QC), a geological consultant for Radisson and a Qualified Person for purposes of NI 43-101. Mr. Luke Evans, M.Sc., P.Eng., ing, of SLR Consulting (Canada) Ltd., is the Qualified Person responsible for the preparation of the MRE at O'Brien. Each of Mr. Nieminen and Mr. Evans is independent of Radisson and the O'Brien Gold Project.

About Radisson Mining

Radisson is a gold exploration company focused on its 100% owned O'Brien Gold Project, located in the Bousquet-Cadillac mining camp along the world-renowned Larder-Lake-Cadillac Break in Abitibi, Québec. A July 2025 Preliminary Economic Assessment described a low cost and high value project with an 11-year mine life and significant upside potential based on the use of existing regional infrastructure. Indicated Mineral Resources are estimated at 0.58 million ounces (2.20 million tonnes at 8.2 g/t Au), with additional Inferred Mineral Resources estimated at 0.93 million ounces (6.67 million tonnes at 4.4 g/t Au). Please see the NI 43-101 "Technical Report on the O'Brien Project, Northwestern Québec, Canada" effective March 2, 2023 and other filings made with Canadian securities regulatory authorities available at www.sedarplus.ca for further details and assumptions relating to the O'Brien Gold Project.

Figure 2: Cross Section through the O'Brien mine including drill holes OB-24-337, and W1-W7

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Figure 3: Vein Modelling Across Drill Holes OB-25-337, and W1-W7

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Table 2: Detailed Assay Results (see "Notes on Calculation of Drill Intercepts")

Table 3: Drill Hole Collar Information for Holes contained in this News Release

Notes:
Hole DDH-24-337 Pilot was previously published on December 16, 2024. Hole lengths for wedges represent meterage from point of wedge.

Forward-Looking Statements

This news release contains "forward-looking information" within the meaning of the applicable Canadian securities legislation that is based on expectations, estimates, projections, and interpretations as at the date of this news release. Forward-looking statements including, but are not limited to, statements with respect to the ability to execute the Company's plans relating to the O'Brien Gold Project as set out in the Preliminary Economic Assessment; the Company's ability to complete its planned exploration and development programs; the absence of adverse conditions at the O'Brien Gold Project; the absence of unforeseen operational delays; the absence of material delays in obtaining necessary permits; the price of gold remaining at levels that render the O'Brien Gold Project profitable; the Company's ability to continue raising necessary capital to finance its operations; the ability to realize on the mineral resource and mineral reserve estimates; assumptions regarding present and future business strategies, local and global geopolitical and economic conditions and the environment in which the Company operates and will operate in the future;, planned and ongoing drilling, the significance of drill results, the ability to continue drilling, the impact of drilling on the definition of any resource, and the ability to incorporate new drilling in an updated technical report and resource modelling; the Company's ability to grow the O'Brien Gold Project; the ability to negotiate and execute an arrangement with IAMGOLD related to the Doyon Mill on satisfactory terms or at all; and the ability to convert inferred mineral resources to indicated mineral resources.

Any statement that involves discussions with respect to predictions, expectations, interpretations, beliefs, plans, projections, objectives, assumptions, future events or performance (often but not always using phrases such as "expects", or "does not expect", "is expected", "interpreted", "management's view", "anticipates" or "does not anticipate", "plans", "budget", "scheduled", "forecasts", "estimates", "believes" or "intends" or variations of such words and phrases or stating that certain actions, events or results "may" or "could", "would", "might" or "will" be taken to occur or be achieved) are not statements of historical fact and may be forward-looking information and are intended to identify forward-looking information. Except for statements of historical fact relating to the Company, certain information contained herein constitutes forward-looking statements Forward-looking information is based on estimates of management of the Company, at the time it was made, involves known and unknown risks, uncertainties and other factors which may cause the actual results, performance or achievements of the companies to be materially different from any future results, performance or achievements expressed or implied by such forward-looking information. Such factors include, among others; the risk that the O'Brien Gold Project will never reach the production stage (including due to a lack of financing); the Company's capital requirements and access to funding; changes in legislation, regulations and accounting standards to which the Company is subject, including environmental, health and safety standards, and the impact of such legislation, regulations and standards on the Company's activities; price volatility and availability of commodities; instability in the global financial system; the effects of high inflation, such as higher commodity prices; the risk of any future litigation against the Company; changes in project parameters and/or economic assessments as plans continue to be refined; the risk that actual costs may exceed estimated costs; geological, mining and exploration technical problems; failure of plant, equipment or processes to operate as anticipated; accidents, labour disputes and other risks of the mining industry; delays in obtaining governmental approvals or financing; risks relating to the drill results at O'Brien; the significance of drill results; and the ability of drill results to accurately predict mineralization. Although the forward-looking information contained in this news release is based upon what management believes, or believed at the time, to be reasonable assumptions, the parties cannot assure shareholders and prospective purchasers of securities that actual results will be consistent with such forward-looking information, as there may be other factors that cause results not to be as anticipated, estimated or intended, and neither the Company nor any other person assumes responsibility for the accuracy and completeness of any such forward-looking information. The Company believes that this forward-looking information is based on reasonable assumptions, but no assurance can be given that these expectations will prove to be correct and such forward-looking statements included in this press release should not be unduly relied upon. The Company does not undertake, and assumes no obligation, to update or revise any such forward-looking statements or forward-looking information contained herein to reflect new events or circumstances, except as may be required by law. These statements speak only as of the date of this news release.

Please refer to the "Risks and Uncertainties Related to Exploration" and the "Risks Related to Financing and Development" sections of the Company's Management's Discussion and Analysis dated April 29, 2025 for the years ended December 31, 2024, and the Company's Management's Discussion and Analysis dated May 28, 2025 for the three-months ended March 31, 2025, all of which are available electronically on SEDAR+ at www.sedarplus.ca. All forward-looking statements contained in this press release are expressly qualified by this cautionary statement.

Neither the TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in the policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this news release. No stock exchange, securities commission or other regulatory authority has approved or disapproved the information contained herein.

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